I. Field of the Invention
The present invention relates generally to fuel injector assemblies and, more particularly, to a fuel injector assembly for use with a twist lock fuel injector.
II. Description of Related Art
Many modern day internal combustion engines of the type used in automotive vehicles utilize fuel injectors for injecting fuel into the internal combustion chambers. For example, in a direct injection internal combustion engine, a discharge end of the fuel injector is open directly to the internal combustion chamber.
In order to overcome the high pressures present within the internal combustion engine and still obtain adequate injection of the fuel for a direct injection engine, these previously known fuel injection systems typically include a fuel rail which is pressurized with high pressure fuel. A fuel cup is fluidly connected to the fuel rail for each fuel injector.
An elongated fuel injector is associated with each cup and each fuel injector includes a fuel inlet as well as a fuel outlet. The inlet end of the fuel injector is axially inserted into a cavity formed in its associated fuel cup and the cup and fuel injector are then secured together. Additionally, an electrical connector extends laterally outwardly from each fuel injector for connection to the control system to control the opening and closure of each fuel injector.
There have been several different approaches for connecting the fuel injector to its associated fuel cup. For example, in one type of fuel injector system, a locking clip extends through receiving slots formed in both the fuel cup as well as the injector housing in order to lock the fuel injector and cup together against axial movement. These retaining clips, however, are not only fairly expensive to manufacture, but the installation of such fuel clips is relatively difficult to achieve. This, in turn, increases not only the labor cost of assembling the fuel injectors to the fuel rail, but also the possibility of a fuel injector that is improperly attached to its associated cup.
An improvement to this previously known type of fuel injector system is disclosed in U.S. patent application Ser. No. 12/852,905, entitled “Fuel Injector Holder”, filed on Aug. 9, 2010. In this fuel injector system, a twist lock is created between the fuel injector and its associated fuel cup in order to lock the fuel injector and fuel cup together.
Although the twist lock system is fully described in the aforementioned U.S. patent application Ser. No. 12/852,905, in brief the injector body includes an outwardly extending plate attached at a position between its ends. This plate includes at least one radially outwardly extending tab so that the cross-sectional area of the plate is noncircular.
A fuel cup receives the fuel inlet end of the fuel injector and the fuel cup includes a radially inwardly extending ledge at a mid position along the longitudinal length of the cavity. The ledge, furthermore, includes a through bore complementary in shape to the shape of the plate. Consequently, with the fuel injector and plate aligned at a predetermined angular position relative to each other, the plate can pass through the ledge upon insertion of the fuel injector into the cavity. Thereafter, the fuel injector is rotated to a locking position in which the tabs on the injector plate are positioned above the fuel cup ledge thus locking the fuel injector to the fuel cup against longitudinal movement.
In order to retain the fuel injector and fuel cup together, it is necessary to lock the fuel injector and fuel cup together against rotation relative to each other. One prior method to accomplish this was to insert a pin through the fuel cup and into a notch in the fuel injector plate. Although a properly positioned pin proved adequate in preventing relative rotation between the fuel injector and its associated cup, in practice it was difficult not only to assemble the pin to the fuel cup, but also to remove the pin from the fuel cup when removal of the fuel injector was desired.